Integumentary system & Wound healing.pptx

# Introduction to the integumentary system and its functions This section provides a foundational understanding of the integumentary system, detailing its essential functions beyond protection, such as vitamin D synthesis, its role as a blood reservoir, and waste excretion, all contributing to overall homeostasis. ## 1. Introduction to the integumentary system and its functions The integumentary system, primarily the skin, plays a crucial role in maintaining the body's internal stability and homeostasis through several vital functions. ### 1.1 The skin's role in homeostasis Homeostasis refers to the body's ability to maintain a constant internal environment despite external changes. The skin contributes significantly to this by regulating temperature, preventing water loss, and participating in metabolic processes. ### 1.2 Key functions of the skin The skin performs a variety of essential functions that support the body's overall health and survival. #### 1.2.1 Vitamin D synthesis * **Process:** The skin manufactures vitamin D when exposed to ultraviolet (UV) radiation from sunlight, specifically wavelengths between 290 and 310 nanometers. * **Importance:** Vitamin D is indispensable for the digestive tract to absorb calcium. Adequate calcium absorption is critical for proper bone growth and maintenance. > **Tip:** While sunlight is essential for vitamin D synthesis, excessive exposure can be harmful. Balancing sun exposure with sun protection is important. #### 1.2.2 Blood reservoir * **Capacity:** The skin houses an extensive network of blood vessels, containing approximately 5% of the body's total blood volume. * **Dynamic Regulation:** In situations of physiological stress, such as shock, the hormone adrenaline triggers vasoconstriction in the skin. This action redirects blood flow away from the periphery to prioritize circulation to vital internal organs. * **Clinical Manifestation:** Consequently, individuals experiencing shock may exhibit paleness, cold extremities, and clammy skin due to reduced blood flow. #### 1.2.3 Excretion of waste products * **Composition of Sweat:** Sweat, primarily composed of 99% water, also contains a small percentage (1%) of other substances. * **Waste Products:** These substances include electrolytes like potassium and sodium chloride, as well as metabolic byproducts such as carbon dioxide, urea, and ammonia. Sweating thus serves as a minor route for eliminating these waste materials from the body. ### 1.3 Overview of integumentary system objectives Understanding the integumentary system involves appreciating its multifaceted contributions to homeostasis. Key objectives include defining fundamental homeostatic principles, explaining how homeostatic systems operate, and assessing the consequences of homeostatic breakdown, with the skin serving as a prime example of a system involved in these processes. --- # Structure and cellular components of the skin This section details the layered structure of the skin, the types of cells within its epidermis, and the process of epidermal renewal. ### 2.1 Layers of the skin The skin is comprised of three primary layers: the epidermis, dermis, and hypodermis. #### 2.1.1 Epidermis The epidermis is the outermost layer of the skin. It is predominantly composed of keratinocytes, which produce the protein keratin. This keratin provides the epidermis with its tough protective barrier. The epidermis is avascular, meaning it does not have its own blood supply. It consists of five distinct strata, or layers, which are arranged from the deepest to the most superficial: * **Stratum basale:** This is the deepest layer and is the most nourished. It contains stem cells that can differentiate into either keratinocytes or other skin cells. Cells from this layer are continuously pushed upwards towards the skin's surface. * **Stratum spinosum:** Cells in this layer are characterized by spiny projections that interlock as they mature. * **Stratum granulosum:** Cells in this layer begin to flatten and accumulate granules of keratin. * **Stratum lucidum:** This layer is characterized by dead cells and is primarily found in hairless regions with thicker skin, such as the palms of the hands and the soles of the feet. * **Stratum corneum:** This is the outermost and thickest layer, composed of flattened, dead skin cells (keratinocytes). Its thickness contributes significantly to the skin's toughness and its ability to resist the external environment. Skin renewal occurs from the stratum basale upwards, with the entire process of shedding and replacing skin cells taking approximately 25 to 45 days. #### 2.1.2 Dermis The dermis is the thickest layer of the skin. It is rich in a matrix of collagen and elastin proteins, which provide structural support, flexibility, and resilience. The dermis also houses several functional structures that enable interaction with the external environment. These include: * Nerve endings * Sudoriferous (sweat) glands * Sebaceous (oil) glands * Hair follicles * Blood vessels * Lymphatics The dermis is also where mechanoreceptors, responsible for sensing touch and pressure, are located. Blood vessels supplying the epidermis are found within the dermis, and damage to this layer can lead to significant blood loss. #### 2.1.3 Hypodermis Also known as the subcutaneous layer, the hypodermis is the deepest layer of the skin, located below the dermis. It consists of fat and connective tissue. Its primary functions include insulating the body, protecting internal organs, and storing fat for future energy use. The thickness of the hypodermis can vary considerably throughout the body and between individuals. ### 2.2 Cells of the epidermis and their functions The epidermis is populated by several types of cells, each with specific roles: * **Keratinocytes:** These are the most abundant cells in the epidermis. They produce keratin, a tough protein that forms the primary protective barrier of the skin. * **Melanocytes:** These cells are responsible for producing melanin, the pigment that determines skin color and provides protection against ultraviolet (UV) radiation from the sun. * **Langerhans cells:** These are specialized epidermal dendritic cells that function as immune cells. They are adept at sensing the presence of bacterial or viral infections and initiating an immune response. * **Merkel cells:** These cells act as touch receptors, playing a crucial role in the sense of touch by detecting light pressure and fine textures. > **Tip:** Understanding the distinct layers and cell types of the epidermis is crucial for comprehending how the skin functions as a protective barrier and how it responds to injury and environmental factors. ### 2.3 Skin renewal The process of skin renewal is a continuous cycle driven by the proliferation of cells in the stratum basale. These newly formed cells migrate upwards through the epidermal layers, undergoing differentiation and eventually becoming flattened, dead cells in the stratum corneum, which are then shed. This entire cycle, from the generation of new cells to their eventual shedding, takes approximately 25 to 45 days. --- # Wound types and the initial stages of wound healing This section details various classifications of open wounds and outlines the initial physiological responses of the body to injury, focusing on the critical phases of hemostasis and inflammation. ### 3.1 Types of open wounds An open wound is an injury that involves a break in the body's tissue, typically the skin, allowing for external or internal exposure. These wounds can arise from various causes, including falls, accidents with sharp objects, and severe trauma. #### 3.1.1 Classification by cause Wounds are often classified based on the mechanism of injury: * **Abrasion:** Occurs when the skin is rubbed or scraped against a rough surface, such as in "road rash." Bleeding is usually minimal, but thorough cleaning is essential to prevent infection. * **Laceration:** A deep cut or tearing of the skin. Accidents involving knives, tools, or machinery are common causes. Deep lacerations can result in significant and rapid blood loss. * **Puncture:** A small hole created by a long, pointed object like a nail or needle, or by a projectile such as a bullet. While bleeding may be limited, these wounds can be deep and potentially damage internal organs. Medical attention, including a tetanus shot, is advised to prevent infection. * **Avulsion:** Involves the partial or complete tearing away of skin and underlying tissue. These often occur during violent accidents, explosions, or gunshots and are characterized by heavy and rapid bleeding. * **Incision:** Refers to any cut or gash, but is most commonly associated with surgical cuts made intentionally during medical procedures. #### 3.1.2 Amputation Amputation is the surgical or traumatic loss of a body part, such as a limb or digit. This can have profound effects on an individual's mobility, independence, and emotional well-being. Post-amputation complications can include persistent pain and phantom limb phenomena. ### 3.2 The initial stages of wound healing The body possesses an inherent ability to initiate a wound healing process upon injury. The initial stages are critical for controlling bleeding and preparing the site for tissue repair. #### 3.2.1 Hemostasis Hemostasis is the immediate physiological response to injury, with the primary goal of stopping blood loss. This is the first crucial step in the wound healing cascade. * **Mechanism:** When blood vessels are damaged, they constrict to reduce blood flow. Components within the blood, specifically platelets and clotting factors, are mobilized to the injured site. Platelets aggregate and, in conjunction with clotting factors, form a sticky plug or fibrin clot that seals the damaged vessel. * **Distinction from Homeostasis:** It is important not to confuse hemostasis (blood clotting) with homeostasis (the body's ability to maintain a stable internal environment). * **Process:** Once damage to the vessel lining (endothelium) occurs, blood exits the vessel, signaling an emergency. The body mobilizes platelets to the leakage site. Platelets then combine with fibrin to form a clot, reducing further blood loss. > **Tip:** Hemostasis is essential for survival as it prevents excessive blood loss and sets the stage for subsequent healing processes. #### 3.2.2 Inflammation Inflammation typically begins within minutes to hours of the injury and can persist for several days. It is a vital part of the immune response. * **Purpose:** During this phase, white blood cells are deployed to the wound site to combat potential infection and clear away debris from the damaged tissue. * **Cardinal Signs:** Inflammation is characterized by four cardinal signs: * **Redness (Rubor):** Caused by vasodilation (widening) of blood vessels, which increases blood flow to the area. * **Heat (Calor):** Resulting from increased blood flow and cellular activity in the affected region. * **Swelling (Tumor/Edema):** Occurs as blood vessels become more permeable, allowing fluid to leak into the surrounding tissues. * **Pain (Dolor):** Triggered by inflammatory chemicals that activate pain receptors, alerting the brain to the injury. * **Chemical Mediators:** Inflammatory chemicals, such as histamine, bradykinin, and prostaglandins, play a key role in producing these signs and symptoms. Histamine, for example, causes vasodilation and increased vascular permeability. * **Chemotaxis:** The inflammatory chemicals also attract other white blood cells to the wound site. This chemical attraction is known as chemotaxis. Key phagocytic cells involved include neutrophils and macrophages, which engulf and remove bacteria and cellular debris. > **Example:** After accidentally cutting your finger, you might observe redness around the cut, feel warmth, notice slight swelling, and experience pain. These are all indicators that the inflammatory phase of healing is actively underway. --- # Pressure ulcers and nursing interventions Pressure ulcers are preventable injuries to the skin and underlying tissue, primarily caused by prolonged pressure, and nurses play a critical role in their prevention and care. ### 4.1 Introduction to pressure ulcers Pressure ulcers, also known as bedsores or decubitus ulcers, are localized injuries to the skin and/or underlying tissue, usually over a bony prominence, as a result of pressure, or pressure in combination with shear. Prolonged pressure impairs blood flow to the affected area, leading to tissue ischemia and damage. ### 4.2 Causes of pressure ulcers The primary cause of pressure ulcers is sustained pressure on the skin, which can be caused by: * **External pressure:** This occurs when the body is immobile, such as in individuals who are bedridden or chair-bound. The pressure is typically concentrated over bony prominences like the sacrum, heels, hips, and elbows. * **Shear:** This is a force that occurs when layers of tissue are pulled in opposite directions. For example, when a patient slides down in bed, the skin might be pulled in one direction while the underlying bone moves in another, causing damage to blood vessels and tissues. * **Friction:** This is the rubbing of skin against a surface, which can damage the epidermis and make it more susceptible to pressure. ### 4.3 Risk factors for pressure ulcers Several factors can increase an individual's susceptibility to developing pressure ulcers: * **Immobility:** This is the most significant risk factor. Conditions that limit mobility, such as paralysis, stroke, surgery, or debilitating illnesses, necessitate constant repositioning to relieve pressure. * **Sensory impairment:** Reduced sensation, such as that experienced by individuals with spinal cord injuries or neuropathy, can prevent them from feeling discomfort and repositioning themselves, thus increasing the risk of prolonged pressure. * **Poor nutrition:** Inadequate intake of protein, vitamins, and minerals can compromise skin integrity and delay healing, making the skin more vulnerable. * **Moisture:** Excessive moisture from incontinence (urine or feces), perspiration, or wound drainage can macerate the skin, making it fragile and prone to breakdown. * **Impaired circulation:** Conditions affecting blood flow, such as peripheral vascular disease or diabetes, can reduce the delivery of oxygen and nutrients to the tissues, making them more susceptible to damage from pressure. * **Fever:** Elevated body temperature can increase the metabolic rate and the skin's need for oxygen, making it more vulnerable to pressure-induced injury. * **Age:** Older adults often have thinner, less elastic skin and reduced subcutaneous fat, making them more prone to pressure-related damage. * **Medical devices:** Devices like oxygen tubing, casts, or splints can exert localized pressure on the skin, leading to ulcer formation. ### 4.4 Pressure ulcer staging Pressure ulcers are categorized into four stages, based on the depth of tissue damage: * **Stage I:** * **Description:** Intact skin with non-blanchable redness. The affected area may be painful, firm, or mushy, and warmer or cooler than surrounding tissue. * **Appearance:** The skin remains red even when pressure is relieved. * **Stage II:** * **Description:** Partial-thickness skin loss involving the epidermis, dermis, or both. The ulcer appears as a shallow, open ulcer with a red-pink wound bed, without slough. It may also appear as an intact or ruptured serum-filled blister. * **Appearance:** Looks like a shallow crater or an abrasion. * **Stage III:** * **Description:** Full-thickness tissue loss involving damage or necrosis of subcutaneous tissue that may extend down to, but not through, the underlying fascia. The ulcer appears as a deep crater, with or without undermining and tunneling. * **Appearance:** The wound bed may contain slough (yellowish dead tissue) and may have exudate or drainage. Bone, tendon, or muscle are not exposed. * **Stage IV:** * **Description:** Full-thickness tissue loss with exposed bone, tendon, or muscle. Slough or eschar (black, leathery dead tissue) may be present. The ulcer often includes undermining and tunneling. * **Appearance:** The deepest stage, with significant tissue destruction. * **Unstageable:** * **Description:** Full-thickness tissue loss in which the base of the ulcer is covered by slough (yellow, tan, gray, green, or brown) or eschar (tan, brown, or black) in the wound bed. The true depth of the ulcer cannot be determined until these are removed. * **Deep tissue pressure injury (DTPI):** * **Description:** Localized discolored intact skin or a blood-filled blister caused by damage of underlying soft tissue from prolonged pressure and/or shear. The area may be purple or maroon and may further evolve rapidly to expose a visibly deep tissue injury even with optimal care. * **Appearance:** The tissue beneath the skin is damaged, and the surface may appear bruised. ### 4.5 Nursing role in pressure ulcer care and prevention Nurses are at the forefront of pressure ulcer prevention and management. Their responsibilities include: * **Risk assessment:** Regularly assessing patients for risk factors using validated tools (e.g., Braden Scale). * **Prevention strategies:** Implementing proactive measures to prevent ulcer formation. * **Early detection:** Identifying the earliest signs of skin breakdown. * **Documentation:** Accurately documenting assessment findings, interventions, and patient responses. * **Collaboration:** Working with other healthcare professionals to develop and implement comprehensive care plans. * **Patient and family education:** Educating patients and their families about pressure ulcer prevention and management. ### 4.6 Prevention strategies Effective prevention of pressure ulcers relies on a multi-faceted approach: * **Repositioning:** * Regularly repositioning patients to relieve pressure. Guidelines often recommend turning patients at least every two hours, or more frequently for high-risk individuals. * Utilizing proper turning and repositioning techniques to avoid shear and friction. * **Skin care:** * Keeping the skin clean and dry, especially in areas prone to moisture. * Using gentle cleansing agents and emollients to maintain skin hydration and integrity. * Avoiding harsh soaps and vigorous rubbing. * Managing incontinence promptly and using moisture-barrier creams. * **Support surfaces:** * Using specialized mattresses, overlays, or cushions designed to redistribute pressure. * These can include foam, gel, or air-filled surfaces. * **Nutrition and hydration:** * Ensuring adequate intake of protein, fluids, vitamins, and minerals to support skin health and healing. * Consulting with a dietitian if necessary. * **Mobility promotion:** * Encouraging and facilitating early mobilization and range-of-motion exercises as tolerated. * **Education:** * Educating patients and their caregivers about the importance of skin care, repositioning, and identifying early signs of skin breakdown. * **Device management:** * Regularly inspecting the skin for pressure points beneath medical devices and repositioning devices as appropriate. ### 4.7 Nursing interventions for existing pressure ulcers For patients who have developed pressure ulcers, nursing interventions focus on promoting healing and preventing complications: * **Wound assessment:** Thoroughly assessing the ulcer, including its size, depth, appearance, exudate, and presence of any tissue type (granulation, slough, eschar). * **Cleansing:** Gently cleansing the wound with a non-cytotoxic solution to remove debris and exudate. * **Debridement:** Removing non-viable tissue (slough and eschar) to promote healing. This can be achieved through various methods, including surgical, enzymatic, autolytic, or mechanical debridement. * **Dressing selection:** Choosing appropriate dressings based on the wound characteristics (e.g., absorptive dressings for heavy exudate, moist dressings for dry wounds). Dressings should maintain a moist wound environment conducive to healing. * **Infection control:** Monitoring for signs of infection and implementing appropriate interventions, such as topical or systemic antimicrobials if indicated. * **Pain management:** Assessing and managing wound-related pain. * **Nutritional support:** Ensuring adequate nutrition to support tissue repair. * **Offloading pressure:** Continuing to relieve pressure from the ulcerated area. > **Tip:** Consistent and accurate documentation of pressure ulcer assessments and interventions is crucial for monitoring progress, communicating with the healthcare team, and ensuring continuity of care. > **Example:** A nurse assesses a Stage III pressure ulcer on a patient's sacrum. The wound is 3 cm in diameter and 2 cm deep, with visible subcutaneous fat and some yellow slough. The nurse decides to use an enzymatic debriding ointment and cover the wound with a hydrocolloid dressing to promote autolytic debridement and maintain a moist healing environment. The patient is also repositioned every two hours, and their nutritional intake is monitored. --- # Advanced stages of wound healing and repair mechanisms This topic explores the latter phases of wound healing, focusing on proliferation and remodeling, and differentiates between healing by primary and secondary intention. ### 5.1 Wound healing overview Wound healing is a complex, multi-stage process that the body initiates to repair damaged tissue. While the initial stages involve controlling bleeding and inflammation, the subsequent phases are dedicated to rebuilding and strengthening the injured area. ### 5.2 Stages of wound healing Wound healing typically progresses through four overlapping stages: 1. **Hemostasis:** This is the immediate response to injury, aimed at stopping blood loss. Blood vessels constrict, and platelets aggregate to form a clot, sealing the wound. 2. **Inflammation:** Beginning within hours of injury and lasting for days, this phase involves white blood cells combating infection and clearing debris. It is characterized by redness, heat, swelling, and pain due to vasodilation, increased vascular permeability, and the release of inflammatory chemicals. 3. **Proliferation:** This stage, which starts a few days post-injury and can last for weeks, is where active tissue reconstruction occurs. Fibroblasts synthesize collagen and extracellular matrix components, new blood vessels form, and keratinocytes multiply to cover the wound surface. 4. **Remodeling:** The final stage, which can span months or years, involves reorganizing and strengthening the newly formed tissue. Collagen is refined, improving the wound's tensile strength, and the tissue gradually regains more of its original structure and function, although scar tissue may differ from the original. #### 5.2.1 The proliferative phase The proliferative phase is critical for rebuilding the wound. Key events include: * **Fibroblast activity:** Fibroblasts are the primary cells responsible for this phase. They migrate to the wound site and begin synthesizing and depositing collagen, which provides structural integrity. They also produce other components of the extracellular matrix. * **Angiogenesis:** The formation of new blood vessels is essential to supply the growing tissue with oxygen and nutrients. This process is driven by growth factors released at the wound site. * **Epithelialization:** Keratinocytes, the main cells of the epidermis, proliferate and migrate across the wound surface from the wound edges, forming a new epidermal layer. #### 5.2.2 The remodeling phase (maturation phase) The remodeling phase is characterized by the maturation and strengthening of the newly formed tissue. This involves: * **Collagen reorganization:** The collagen initially laid down during proliferation is disorganized. In the remodeling phase, it is reoriented along lines of tension, increasing the wound's tensile strength. * **Collagen cross-linking:** Further cross-linking of collagen fibers occurs, making the scar tissue stronger and more resilient. * **Apoptosis:** Unnecessary cells and blood vessels that were formed during proliferation undergo programmed cell death (apoptosis). * **Scar maturation:** Over time, the scar tissue becomes less red, flatter, and softer. While it can regain significant strength, it typically only reaches about 80% of the tensile strength of the original, uninjured skin. > **Tip:** The remodeling phase can last for a very long time, and its success is influenced by factors such as the wound's size, depth, and the individual's overall health. ### 5.3 Types of wound healing intention Wounds can heal by one of two primary intentions, depending on the characteristics of the wound and the management employed: #### 5.3.1 Healing by primary intention (first intention) * **Definition:** This type of healing occurs in wounds where the edges are clean, well-approximated (brought together), and there is minimal tissue loss. Surgical incisions are a classic example. * **Process:** * The wound is initially managed with sutures, staples, or surgical glue to ensure the edges are in close contact. * This close approximation facilitates rapid healing with minimal inflammation and scar formation. * The proliferative phase is relatively short, and the remodeling phase is less extensive. * **Outcome:** A thin, often barely visible scar. #### 5.3.2 Healing by secondary intention (second intention) * **Definition:** This type of healing occurs in wounds with significant tissue loss, irregular edges, or where the wound cannot be easily approximated. Examples include large traumatic wounds, chronic ulcers, or burns. * **Process:** * These wounds heal by granulation, contraction, and epithelialization. * **Granulation:** The wound bed fills with new connective tissue and blood vessels. This is a "beefy red" appearance, indicating healthy tissue regeneration. * **Contraction:** Specialized cells called myofibroblasts at the wound edges pull the wound together, reducing its size. * **Epithelialization:** Keratinocytes migrate across the granulation tissue from the wound edges. This process is slower than in primary intention healing. * **Outcome:** Wider, often more noticeable scars. The healing process takes longer due to the need for granulation and contraction. > **Example:** A deep surgical wound that is left open to heal by secondary intention will gradually fill with granulation tissue from the bottom up, the edges will slowly pull inward, and new skin will form across the surface, leading to a larger scar compared to a similar wound closed surgically. --- ## Common mistakes to avoid - Review all topics thoroughly before exams - Pay attention to formulas and key definitions - Practice with examples provided in each section - Don't memorize without understanding the underlying concepts

| Term | Definition | |------|------------| | Integumentary System | The organ system that includes the skin and its appendages, responsible for protection, sensation, temperature regulation, and excretion. | | Homeostasis | The ability of the body to maintain a stable internal environment despite changes in external conditions. | | Epidermis | The outermost layer of the skin, composed of keratinocytes and providing a protective barrier against the environment. | | Dermis | The layer of skin beneath the epidermis, containing collagen and elastin for support and flexibility, as well as blood vessels, nerves, and glands. | | Hypodermis | The layer of subcutaneous fat and connective tissue below the dermis, providing insulation, protection for internal organs, and fat storage. | | Keratinocytes | Cells in the epidermis that produce keratin, a tough protein that forms the skin's protective barrier. | | Melanocytes | Cells in the epidermis that produce melanin, a pigment that protects the skin from UV radiation and determines skin color. | | Langerhans cells | Epidermal dendritic cells that function as immune cells, sensing bacterial or viral infections within the skin. | | Merkel cells | Specialized cells in the epidermis that act as touch receptors, enabling the sense of touch. | | Vasoconstriction | The narrowing of blood vessels, which reduces blood flow to an area, often occurring during shock to redirect blood to vital organs. | | Excretion | The process of eliminating waste products from the body, for example, through sweat which contains water, salts, and metabolic waste. | | Abrasion | A wound caused by the skin rubbing or scraping against a rough or hard surface, often resulting in superficial damage. | | Laceration | A deep cut or tearing of the skin, typically caused by sharp objects or blunt force trauma. | | Avulsion | A wound where skin and underlying tissue are partially or completely torn away from the body. | | Incision | A clean cut or gash, commonly made during surgical procedures. | | Puncture | A small hole in the skin caused by a pointed object, such as a nail or needle. | | Amputation | The surgical or traumatic removal of a limb or other body part. | | Hemostasis | The first stage of wound healing, where bleeding is stopped through blood clotting. This process involves platelets and clotting factors to form a plug at the injury site. | | Inflammation | The second stage of wound healing, characterized by redness, swelling, heat, and pain, as the body's immune system fights infection and clears debris. | | Proliferation | The third stage of wound healing, involving the rebuilding of damaged tissue with new collagen and blood vessels, and the formation of new skin layers. | | Remodeling | The final stage of wound healing, where newly formed tissue is strengthened and reorganized to improve tensile strength and regain function. | | Pressure ulcer | A localized injury to the skin and underlying tissue, usually over a bony prominence, resulting from pressure, or pressure in combination with shear. | | Chemotaxis | The movement of white blood cells towards a site of infection or injury, guided by chemical signals released by damaged tissues or pathogens. | | Phagocytes | Cells, such as neutrophils and macrophages, that engulf and digest cellular debris, foreign substances, microbes, cancer cells, and anything else that does not have the right markers of self-recognition on its cell surface. | | Primary intention healing | A type of wound healing that occurs when wound edges are clean, closely approximated, and have minimal tissue loss, resulting in faster healing and minimal scarring. | | Secondary intention healing | A type of wound healing that occurs in wounds with significant tissue loss or gaping edges, where the wound is left open to heal by granulation, contraction, and epithelialization from the base up. |